Synchronous running gear for airplanes



July 21, 1931. J. BLONDIN 1,815,182

SYNCHRONOUS RUNNING GEAR FOR AIRPLANES Filed Aug. 20. 1929 2 Sheets-Sheet l I 7 v a I a a 7\ 5t J5 INVENTOR,

aw/ m ATTORNEY":

July 21, 1931. J. BLONDIN 1,815,182

SYNCHRONOUS RUNNING GEAR FOR AIRPLANES Filed Aug. 20, 1929 2 Sheets-Sheet 2 INVENTOR) Jae "a7? .27071 dz 72 BY I 7A TTORNEY Patented July 21, 1931 PATNT FFEQE JOSEPH BLONDIN, OF LOS ANGELES, CALIFORNIA SYN CHRON'OUS RUNNING GEAR FOR AIRPLANES Application filed August 20, 1929.

This invention relates to under-carriage or running-gear of airplanes, and particularly to what is commonly called the axle-less type.

Conventional axle-less types of airplane running-gear embody wheels carried on short spindles pro ecting from the apex of trla-ngular frames whose bases are hinged to the gear systems impose detrimental and total.

fuselage or to a central frame extending below the fuselage, as here shown.

In some types the bases of the triangular frame are hinged below the fuselage in which case the thrust rods act as compression members between the wheels and the cushioning devices carried by the fuselage.

In other cases a reverse action is employed; that is triangular frames whose bases are hinged to the fuselage, and parts acting as tension members between the wheels and said cushioning devices in this case carried by the central frame below the fuselage. In either and both cases the wheels are forced to follow an upward and outward path-the latter motion tending to strip the tires from the wheels and impose other detrimental wear and tear effects upon said tires and wheels. It is to be noted that all such runningstatic loads and dynamic loads directly upon the fuselage frame-work which is weakened by repeated compressions, shocks and vibration stresses. Also,'all static loads and landing loads are imposed upon the cantilever wheel spindles, tending to up-bend the spindles and throw the wheels out of alignment.

Airplane wheels and axle or spindle are notto be classed with other vehicles which merely roll along the ground. Airplanes are distinctive in being subject to landing loads.

The U. S. Department of Commerce, Aeronautics Branch, estimates that the landing load is equal to an averageof four times the static load.

All such conventional types of running-.

gear systems are also characterized by independent actions as regards the right-hand and left-hand wheels respectively; that is to say, no operation or lip-throw of the right wheel as in running over an obstruction.

Serial No. 387,161.

has any connective effect upon the left wheel or vice-versa.

Also, such systems, landing in long grass, grain fields, etc., have a tendency to gather the grass, grain, etc., into the angle or crotch formed by the wheels and their frames, tending to throw the airplane over on its nose, to crack up propeller or cause more serious damage.

An object, therefore, of this invention is to provide a type of running-gear which shall be axle-less and which provides novel fundamentally difierent and advantageous features over the conventional types.

This invention embodies a running gear. wherein the right hand and the left hand system of frames and wheels operate conjunctively and conjointly at all times; the frames being hinged along lines directly across or at right angles to the length of the airplane fuselage, and are designed to oscil late equally and synchronously backward and upward.

The function attained by such similar and simultaneous rear and up movement is a maximum cushioning of shock of impact of ground preceding a flight thereby spilling I the air at the wing tips, and securing under the wings air pressure whose resultant is di rected alternately and oppositely at angles divergent from the vertical thereby reducing the over-all direct lift of the machine and increasing the length of ground run to get into the air.

A function attained by the simultaneous and equal actions of the running g ar of hi invention is that of ma nta n ng the airpl ne on an even keel, whereby its wings attack the air always horizontally, securing maximum lift effort and shortening the ground run necessary to attain flight.

The independert side-action of c-onven tional running-gears introduce another disturbance and disadvantage due to the fact that one wheel and spring is depressed and overloaded, as compared to its mate, the airplane is mace to banlt or lean toward said overloaded side which introduces a turning or steering action necessitating strenuous corrective effort on the part of the pilot through the medium of the machines directive rudder.

or tail skid.

A further object, therefore, is to provide a runninggear system whose wheels are made to operate conjunctively and simultaneousiy inthe same manner and direction wherebv ground loopingv and consequent turning is minimized and the tendency of the airplane is made to automatically and inherently maintain true and straight-away trackage along the ground in the direction initially aimed at.

Conventional type running-gears throw the airplane into lateral oscillations when ground running, requiring constant, instant and strenuous corrective action by the pilot on his aileron controls to reestablish and maintain lateral balance in order to prevent wing-tip contact with the ground and resultant damage and injury.

It is another object of the invention to pro vide a running gear system which will automatically maintain the airplane on an even keel while rolling along the ground and minimizing wing-tip crash s and greatly increase the safety factor of this class of vehicles.

Conventional type runn ng gears which carry their wheels on shortspindles inn .e load at one point only,-at their inward conncction with their carrying-frame or at a point immediately adjacent to the sides of the wheel h abs nearest the fuselage. This point also forms a crotch between its carrying frame and the wheel which gathers long grain, weeds, etc, when landing in emergency fields and tends to turn the airplane over on its nose with consequent damage.

Another object is to provide an airplane rrmning system wherein the wheels are each carried by and rotate around a spindle whose ends each support .d by co-hcting frames which are designed to ward oif vegetable growth and form a clear trackage.

The independent, opposite side actions of conventional running-gears are limited in their spring-system to only one-half the total capacity of the springs. if the airplane when landing side slips or swipes against the ground the wheel w h first contacts with theground makes its independent spring absorb the whole shock and stress of landing. This stress frequently over-loads and overstrains the one-side spring system with the result that the wheel jams against the carrying frame and crashes or buckles the frame or wheel, or both.

My present invention aims to provide a running-gearsystem wherein each wheel reacts simultaneously and jointly upon and against all springs employed in the system thereby distributing and minimizing the shock effects. 7

My invention has for general objects the improvement of all existing running-gears for airplanes; which shall be superior in simplicity, strength, design and organization, purposes and positiveness of action, safety, and general efficiency.

An embodiment is herewith illustrated and it is understood that modifications may be resorted to within the spirit, scope and principle of the invention as it is more directly claimed hereinafter and consisting of the disclosed apparatus and its substantial equivalents.

Figure 1 is a plan view of the apparatus.

Figure 2 is a side elevation.

Figure 3 is a diagram of wheel action.

Figure 4 is a front elevation.

Figure 5 is a perspective of a portion of" the frame structure for a spindle.

Figure 6 is a front end diagram of conventional, cantilever, independent spindle and wheel frame.

The running-gear includes wheels 2 and which have hubs mounted upon tubular spinlles 4 which are coaxial and mounted upon nested, parallel rods. These rods a-re'parts of frames as now described.

A front frame includes a transverse shaft 5 ournaled in bearings B carried by the airplane side and floor parts and has rearwardly and downwardly directed arms 5 with parallel side bars 5' which have spindle-support rods 5 turned into the spindle tubes 4', Fig. 5.

An inside arm 6 is fixed to each arm 5 and has an out-turned rod' 6 in the spindle tube, and a diagonal brace 7 reaches from the end of'bar 6 up to the journaled partof' the arm 5*. i

It will be seen that the side bars 5 and arms 6 form firm yokes on the remote ends of the shaft arm 5 to receive the wheel and that the arms 5 serve tooutwardly deflect impinging vegetation during ground runs; the spindle tube being supported at each end.

A rear frame includes a transverse shaft 10, having long, forwardly and downwardlydirected side arms 1 0 which terminate in coaxial, inturned spindle rods 10 in the spin dle tubes 4.

The shaft 10 has a floating support in the form of crank arms 11 of a rock-shaft 12 which is journaled in bearings B on the body of the airplane A.

The spindles of the wheels are at the bottom apices of the triangles formed by the bearings of the frame shafts 5 and 10 and the spindles and these are well back of the vertical plane through the shaft 5 so that when the wheels land they are moved back and up in an arc X on the axis 5 with the result that the cranks 11 are forced rearward in coinpensation. This movement is utilized to impart the shock to a cushioning means includ ing a number of springs 15 which are attached to the shaft 10 and at other ends to shaft 5, so that they are tensioned under the impact shock and absorb heavy strains and greatly reduce stresses and vibrations in the airplane body and fuselage.

Thus the two ground wheels are carried by a pair of mutually jointed frames which act synchronously in all shifting motions of the wheels and distribute the work equally to all of the shock springs simultaneously with manifest advantages in function, efficiency, durability, safety and simplicity.

Also it will be noted that all dynamic loads acting upon and through the wheels in this system are divided into a forward thrust towards the axis 5 and a rearward thrust towards the parts 1012; said loads and thrusts being taken by the spring system and thereby neutralizing and minimizing all dynamic stresses upon the fuselage and relieving this of all but the normal static-load proper.

Preferably a conventional form of snubber 17 is connected to the floating shaft 10 to control its rebound after shock.

For purpose of contrast Figure 6 illustrates a conventional running-gear in which frames 20 are hinged below the fuselage with thrust rods 21 as compression members between the wheels and cushionscarried by the fuselage, or just vice-versa. In either case the wheels are forced into an outward motion which tends to strip the tires and produce other untoward effects. Such systems impose the static and landing loads directly on the fuselage framework with rapid weakening effects. cantilever wheel spindles with serious results, such as bending and disalignment.

What is claimed is:

1. In a running-gear for airplanes, a trussed frame unit including a crank shaft journaled transversely of the longitudinal axis of the airplane and having rigid there-' with, rearward and downward extending side arms whose rear ends carry land wheels on coaxial spindles which are axially unattached and provide clearance.

2. In a runnin ear for airplanes, a

trussed frame unit including a shaft journaled transversely of the longitudinal axis" of the airplane and having rigid rearward and downward extending side arms whose rear ends carry land Wheels on coaxial Also, all loads are imposed on the spindles and cushioning means for the frame including a floating, rigid arm frame hitched to the spindles.

3. In a running-gear for airplanes, a wheel frame journaled transversely of the airplane and having rigid side arms directed rearward thereof and each terminating in forks, and coaxial, spaced spindles in said forks carrying landing wheels and a rocking crank shaft carrying a rigid armed frame attached to said spindles.

In a running-gear for airplanes, a wheel frame journaled transversely of the airplane and having side arms directed rearward thereof and terminating in forks, and coaxial spindles in said forks carrying landing wheels, said spindles including tubes and said forks having ends turned into and supporting the tubes.

5' In a. running-gear for airplanes, a wheel frame ournaled transversely of the airplane and having side arm s directed rearward thereof and terminating in forks, and coaxial spindles in said forks carrying landing wheels, said spindles including tubes and said forks having ends turned into and supporting the tubes and diagonal braces from the forks to the shaft.

6. A running-gear for airplanes including a. wheel-carrying frame with rigid side arms swinging upward and rearward on an axis transverse the airplane. and a floating thrust frame attached to said arms and having a. spring controlled horizontally floating rockor arm support to reciprocate with arcuate swinging upward and rearward on an axis transverse the airplane, and a floating thrust frame attached to said arms and having a rocker arm support to reciprocate with armate movements of the wheel frame, and cushioning means for the swinging arms of the wheel frame and adapted to'absorb full shock on either wheel.

8. A running-gear for airplanes including a wheel carrying frame having an axistransverse to the airplane and an attached rigid" arm thrust-frame. which translates rotary action of the frame into horizontal fore and aft reciprocations, and a synchronizing rock shaft mechanism connected to the thrust frame; whereby the reciprocative actions thereof are equalized.

9. A running-gear for airplanes including a front, frame with a transverse axis and rigid rearward side arms, and a rear frame with a transverse axis and rigidly ]01Iledforward arms pivotally connected to the front frame arms and coaxial land wheels carried at the connection of said frames;

said side arms including outside ward-off forks for the wheels.

10. A running-gear for airplanes including a front shaft with a transverse axis and rigid rearward side arms, and a rear shaft with a transverse axis and forward arms connected to the front frame arms, coaxial land wheels carried at the connection of said arms, and means for cushioning the landing effects of the wheels through the shaft.

11. A runninggear for airplanes including a front frame with a transverse axis and rearward side arms, and a rear frame with a transverse axis and forward arms connected to the front frame arms, coaxial land wheels carried at the connection of said frames, and a: synchronizing crank shaft whose cranks form floating supports for the rear frame.

12. A running-gear for airplanes including a front shaft with a transverse axis and rearward side arms, and a rear shaft with a transverse axis and rigid forward arms connected to the front frame arms, coaxial land. wheels carried at the connection of said arms, and a synchronizing crank shaft whose cranks form floating supports for" the rear frame, and a system of shock absorbing springs which are connected to the rear shaft to resist rearward thrust of the same under reaction of the wheels.

13. A running-gear for airplanes including a front frame with a transverse axis and rearward side arms, and. a rear frame with a transverse axis and forward arm's connected to the front frame arms, coaxial land wheels carried at the connection of said frames, and means for cushioning the landing effects ofthe wheels through the frames, and rebound checking snubbers for said frame system.

14. In an airplane running-gear a spindle, for a wheel, consisting of a tube which is mounted on a support consisting of a set of nestedv rods comprising a group of parallel arms, ends of a running-gear frame system.

15. A running-gear, for airplanes, including a tubular spindle for a wheel, a frame having an arm with a fork whose side bars have inturned rods entering the spindle from opposite ends to form two-point supports therefor.

16. A running-gear, for airplanes, including a tubular spindle for a wheel, a frame having an arm with a fork whose side bars have inturned rods entering the spindle from opposite ends to form two-point supports therefor; said fork passing forward of the wheel to form a ward for impinged vegetation.

17. In running-gear for airplanes, a wheel frame, a thrust frame connected thereto, and a synchronizing means comprising a rock shaft having swinging arms in combination with said frames and forming a system whereby the wheels are connectively and conjunctively operated and made to maintain the same lateral, vertical, and parallel relation at all times.

frames.

J OSEPI-I. BLONDIN. 

